New Technique Generates Stem Cells Without Harming Embryos

Scientists using a new technique report that they have been able to generate human embryonic stem cells (hES) by using a single-cell biopsy that they say does not harm embryos. The technique was described in the August 24, 2006, online edition of Nature.

The technique, called preimplantation genetic diagnosis (PGD), is similar to the technique used in in vitro fertilization (IVF) clinics to assess the genetic health of preimplantation embryos. The resulting cell lines appear to be identical to hES cell lines derived from later-stage embryos using techniques that destroy the embryo's developmental potential. Current technology derives hES cells from the inner cell mass of later-stage embryos known as blastocysts, destroying their potential for further development. The new technique generates hES from a single cell obtained from an eight-cell-stage embryo.

To create the new cell lines, researchers at Advanced Cell Technology (ACT, Alameda, CA, USA) used single cells obtained from unused embryos produced by IVF for clinical purposes. Nineteen stem-cell outgrowths and two stable hES cell lines were obtained. The lines were genetically normal and retained their potential to form all of the cells in the human body.

"We have demonstrated, for the first time, that human embryonic stem cells can be generated without interfering with the embryo's potential for life,” said senior author Robert Lanza, M.D., vice president of research & scientific development at ACT. "Overnight cultures of a single cell obtained through biopsy allow both PGD and the development of stem-cell lines without affecting the subsequent chances of having a child. To date, more than 1,500 healthy children have been born following the use of PGD.”

Those with ethical concerns see problems with the technique. They fear that removing one cell from an embryo is likely to lower the embryo's chances of womb implantation or may alter its development in some way and later cause health problems in the child developed from it. Some critics fear that the cell that is removed may have its potential for developing into a new embryo destroyed. Thus, the new technique joins a long list of others designed to avoid controversy but still posing problems.

"None of those methods was likely to satisfy all the critics, and I don't think this one will either,” said Tom Murray, president of the Hastings Center, a bioethics research institute in Garrison (NY, USA).



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